Valgrind安装与使用

1. 下载：https://www.valgrind.org/docs/manual/manual-core.html#manual-core.started

2. 解压

   tar -xjvf valgrind-3.16.0.tar.bz2
   

3. 安装

   cd valgrind-3.16.0/
   
   ./autogen.sh
   ./configure
   make
   sudo make install
   

   可能需要先安装：

   sudo apt-get install autotools-dev
   sudo apt-get install automake
   

4. 使用

   程序：

   a.c

   #include <stdlib.h>
   
   void f(void)
   {
      int* x = malloc(10 * sizeof(int));
      x[10] = 0;        // problem 1: heap block overrun
   }                    // problem 2: memory leak -- x not freed
   
   int main(void)
   {
      f();
      return 0;
   }
   

   运行：

   gcc -g -o a a.c   
   valgrind --leak-check=yes ./a
   

   输出：

   ==13545== Memcheck, a memory error detector
   ==13545== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
   ==13545== Using Valgrind-3.16.0 and LibVEX; rerun with -h for copyright info
   ==13545== Command: ./a
   ==13545==
   ==13545== error calling PR_SET_PTRACER, vgdb might block
   ==13545== Invalid write of size 4
   ==13545==    at 0x108668: f (a.c:6) # 第6行非法写入，一共是10个元素的int数组，却对x[10]写入
   ==13545==    by 0x108679: main (a.c:11)
   ==13545==  Address 0x522e068 is 0 bytes after a block of size 40 alloc'd
   ==13545==    at 0x4C2FECB: malloc (vg_replace_malloc.c:307)
   ==13545==    by 0x10865B: f (a.c:5)
   ==13545==    by 0x108679: main (a.c:11)
   ==13545==
   ==13545==
   ==13545== HEAP SUMMARY: # 检查出问题
   ==13545==     in use at exit: 40 bytes in 1 blocks
   ==13545==   total heap usage: 1 allocs, 0 frees, 40 bytes allocated
   ==13545==
   ==13545== 40 bytes in 1 blocks are definitely lost in loss record 1 of 1 # 肯定丢失
   ==13545==    at 0x4C2FECB: malloc (vg_replace_malloc.c:307)
   ==13545==    by 0x10865B: f (a.c:5)
   ==13545==    by 0x108679: main (a.c:11)
   ==13545==
   ==13545== LEAK SUMMARY: # 内存泄漏
   ==13545==    definitely lost: 40 bytes in 1 blocks # 肯定丢失的部分，需要处理
   ==13545==    indirectly lost: 0 bytes in 0 blocks
   ==13545==      possibly lost: 0 bytes in 0 blocks
   ==13545==    still reachable: 0 bytes in 0 blocks
   ==13545==         suppressed: 0 bytes in 0 blocks
   ==13545==
   ==13545== For lists of detected and suppressed errors, rerun with: -s
   ==13545== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
   

参考：https://www.jianshu.com/p/7ce24f278b0e

​